1. Field of the Invention
The present invention relates to image processing methods and apparatuses. More particularly, the present invention relates to three-dimensional (3D) display apparatuses and methods.
2. Description of Related Art
Human visual system is capable of finding relative positions of things by using many types of depth clues. Those depth clues include physiological factors such as accommodation, convergence, binocular disparity, motion parallax, etc., and psychological factors such as linear distance, shading, shade distance, hiding by another object, texture grade, color, etc. In the physiological depth clues, accommodation is to vary a focus range of the crystalline lens for the purpose of focusing the eyes on a specific position. The function of accommodation is operating with convergence. Meantime, convergence is to make one's eyes meet at a target point by moving inward when he is gazing into the target point apart from him in a limited distance. Binocular disparity is oriented from the fact that the left and right eyes are arranged to respond respective images because they are spaced from each other in about 65 mm, which means a difference between images incident upon the left and right retinas while looking at a 3D scene. This function of binocular disparity acts as a critical depth clue which is used for depth sense or stereopsis in the human visual system.
A 3D display apparatus is designed to display a 3D image by utilizing such a cognition mechanism of the human visual system. Ever been proposed various types of 3D image display modes, a stereoscopic mode can be regarded as remarkable on the aspect of technical reducibility and 3D display capability at the time when this patent application is filed. In a stereoscopic 3D display system, it is possible to realize depth cognition or stereopsis through simulation with binocular disparity by rendering the left and rights eyes to receive two images that are independently taken by two image sensors spaced in about 64 mm as like human's eyes.
Here, it is necessary to exclude interference by controlling two images forming a couple of stereoscopic images, i.e., the left and right images, to exactly be sent to the left and right eyes of a user. There are several ways to control interference, such as a polarization type (also called passive glasses type or film patterned retarder (FPR) type) in which a phase modulation plate is equipped on a display panel to generate orthogonal polarization from left and right images and the left and right images are respectively incident on user's left and right eyes through polarized filters embedded in glasses of the user, an active glasses type (also called shutter glasses type) in which left and right images are alternately applied to a display panel and a user's active glasses operates to alternately open its left and right shutters, a lenticular type in which a lenticular lens is employed to control a light path, a parallax barrier type in which a parallax barrier electrically generated operates to partly screen and then left and right images are respectively incident on the left and right eyes of a user.
At the times of this application, while the most widely case of the stereoscopic 3D display system is generally known is involved in television sets, there are also many technical approaches to implement the stereoscopic 3D display into monitors of personal computers (PCs), smart phones, and data processing units such as tablet computers. Managing 3D image signals in a data processing unit is normally conducted by means of an application program such as a multimedia player. Comparative to a 2D image playback technique simply decoding an original image signal, changing its format and then playing back the decoded and formatted original image signal, playing back a 3D image could cause an operative burden to be increased as it is necessary to decode the 3D image signal and mix left and right images.
Data processing apparatuses such as desktop or laptop computers are easy to process 3D image signals by application programs because their own microprocessors have sufficient performance in operation. To the contrary, portable apparatuses, such as smart phones or tablet computers, employing embedded slow processors in consideration of power consumption and heat discharge, is insufficient for processing 3D image signals less than high-performance computers do. Therefore, it at present is inevitable for the portable apparatuses to result in low frame or bit rates, or low degree of resolution in playing back 3D images by application programs. Especially, like a system adopting an android platform, in case an application program is composed of binary codes to be processed by a virtual machine such as Dalvic not native codes such as C/C++, an execution rate of the application program deeply downs. Additionally, in playing back a 3D image only by means of an application program, it takes much boot time because the application program becomes larger in volume.
Considering those limitations, some types of portable apparatuses have been playing back 3D images by appending chipsets thereto for the 3D image signal processing in addition to embedded processors. For this function, an android platform is configured to embody hardware acceleration and image processing by external hardware by way of Hardware Abstraction Layer (HAL). However, such an additional chipset could cause the prime cost and price, as well as increasing an occupation area on a printed circuit board of the apparatus.